a ti si ti si
a ti si ti si .
ä WORD_BOUNDARY t̪̻ i WORD_BOUNDARY s̪̻ i WORD_BOUNDARY t̪̻ i WORD_BOUNDARY s̪̻ i WORD_BOUNDARY
a WORD_BOUNDARY t i WORD_BOUNDARY s i WORD_BOUNDARY t i WORD_BOUNDARY s i WORD_BOUNDARY . WORD_BOUNDARY